The present invention relates generally to threaded fasteners, and more particularly to a means for securing a nut on a threaded shaft.
It is well known in the fastener art to provide a plastic insert in a nut that engages the external threads of a bolt in order to make a self-locking nut. It is also known in the art to use keepers such as cotter pins to retain a nut on a threaded shaft. The present invention provides an improvement in the art whereby a nut may be threaded on a shaft and locked in position by a locking wedge whereby the nut is positively retained against accidental angular displacement.
In the presently preferred embodiment of the invention, the nut has an inwardly facing annular channel and an annular plastic insert is positioned in the channel. The nut is constructed to be threaded onto a shaft with the annular plastic insert in engagement with the external threads of the shaft. The shaft is provided with a groove or a keyway in which a wedge shape locking element or keeper is inserted. The locking element is forcibly inserted in the groove and has a pair of inclined surfaces that engage the plastic insert. The wedge prevents accidental rotation of the nut. The engagement between the plastic insert and the inclined surfaces prevent the wedge from being accidentally dislodged.